A study at Dartmouth Medical School suggests that the gradual increase in melanoma rates in the U.S. is more the result of “overdiagnosis” than of any significant change in the actual rates themselves. The results of the study appear in the August 4 issue of BMJ Online First.
The researchers based their conclusion on the observation that has been a significant increase in the rate of early disease while there has been little change in the number of cases of advanced disease or deaths.
Dr. H. Gilbert Welch and colleagues considered data for patients aged 65 and older who participated in the U.S. National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) program from 1986 to 2001.
Analysis showed melanoma increased substantially over time with the average biopsy rate increasing 2.5 times and the incidence of melanoma increasing 2.4 times.
Stage-specific analyses showed that the increase was restricted to in situ and local disease, whereas the incidence of regional and distant disease did not change substantively. Disease-specific mortality remained stable.
Dr. Welch concluded "The combination of a big increase in early disease with little change in advanced disease and little change in mortality argues that overdiagnosis is going on." This, however, does not mean that "there hasn’t been some increase in true disease."
Another possibility is that better treatment is preventing the disease from advancing. Dr. Rhoda Narins, professor of dermatology at New York University School of Medicine and president of the American Society for Dermatologic Surgery believes “we’re finding more melanomas early and treating them."
There has been heightened awareness on the part of the public to monitor skin lesions and marks and to seek medical attention when changes in appearance, size, and color take place. Doctors too are more likely to take aggressive action when a questionable skin lesion appears or changes its characteristics by referring the patient to a dermatologist for a second opinion or remedial care.
Both Narins and Welch agreed any lesions that could possibly be melanomas should be removed. Welch, however, does not support mass skin screenings for people who believe they are healthy. He pointed both to the psychological effects of misdiagnosis and the possible complications of melanoma surgery, which often takes a larger section of skin, in sensitive areas such as the face or buttocks.